The subject invention relates to an improved theft prevention system for use with a business machine such as a typewriter.
The unauthorized taking of business machines, from office settings and the like, has always been a problem due to their portable nature which facilitates rapid pilferage. Today, as the sophistication and cost of business machines escalate, a concomitant rise in the number of thefts has been observed. Research has shown that a large majority of these thefts occur during business hours when offices are understaffed, such as at opening or closing time, as well as at lunchtime. Accordingly, a number of devices have been developed, for reducing the number of machines which are removed without authorization. One type of prior art device functions to sound an alarm when the machine is moved from its resting place. This type of device is effective in reducing business hour crime since the alarm alerts any office personnel, in the general area, to the presence of the thief.
One example of this type of prior art device can be found in U.S. Pat. No. 2,928,336, issued Mar. 15, 1960, to Jagger. The device disclosed in Jagger, which is intended to be housed within a check writing device, includes a switch having a spring biased plunger mechanism which extends downwardly from the base of the device into abutting contact with a planar surface or desk. When the machine is lifted from the desk, the plunger is biased into an active position thereby sounding an alarm. One problem of the Jagger device is that the switch may be tampered with easily thereby disarming the alarm. For example, simply by sliding a thin piece of flexible material under the plunger prior to lifting the machine, a thief is able to prevent the plunger from moving into the active position thereby preventing the alarm from sounding.
One means for overcoming the latter shortcoming may be found in U.S. Pat. No. 3,815,117, issued June 4, 1974 to Gopperton. The latter patent discloses a two way switch, associated with a plunger mechanism. The switch includes an extra contact, above the plunger, such that an alarm will be sounded in response to any movement of the plunger. Thus, the alarm will sound if the machine is raised from the table permitting the plunger to move downwardly. In addition, if a thief attempts to disarm the device by sliding a thin strip underneath the plunger, the resulting upward movement of the plunger will close the extra contact in the switch thereby sounding the alarm. The device disclosed in Gopperton, while providing increased security, requires a relatively complex and costly switch and plunger mechanism. In addition, a skillful and knowledgeable burglar can still disarm the device by totally arresting the movement of the plunger.
Another shortcoming of the prior art devices is that a thief gaining access to the interior of the machine, can rapidly halt the sounding of the alarm thereby decreasing the likelihood of detection. More specifically, while certain machines provide a relatively solid enclosure, a business machine, such as a typewriter, having a removable cover structure, facilitates access to the interior of the machine permitting rapid mechanical dismantling of the alarm.
Accordingly, it is an object of the subject invention to provide a new and improved theft prevention system for use with a business machine which includes a unique guard means, for shielding the plunger mechanism of a switch means, thereby inhibiting any unauthorized tampering with the plunger.
It is another object of the subject invention to provide a theft prevention system for a business machine which includes an elongated protective sleeve that is fixedly connected to a planar resting surface and extends upwardly into the housing of the machine surrounding the plunger mechanism thereby preventing access thereto.
It is a further object of the subject invention to provide a theft prevention system for a business machine which includes an additional switch means that is actuated by relative movement between the base and the cover of the housing thereby increasing the chances of detecting any unauthorized tampering with the machine.
It is still another object of the subject invention to provide a new and improved theft prevention system for business machines which includes a unique locking bracket for releasably securing the cover to the base. The locking bracket is connected to the base by a screw which can be disengaged only when the machine is first upwardly lifted from its resting place thereby actuating an alarm.